Mercury-vapor apparatus.



F. G. KEYES.

MERCURY VAPOR APPARATUS.

APPLICATION FILED 313.11, 191a.

Patented Nov. 18, 1913.

sachusetts, have invented =certain new and;

4 warren PATENT OFFIGE.

-.Ii'BlI?IDII'IRICK(1.'KEYES, 'O'F BOSTON, MSSACHU'SETTSfASSIGNOR TO COOPER HEWITT ELECTRIC COMPANY, OF HOBOKEN, NEW JERSEY, "A CORPORATION 'OF NEW JERSEY.

Specification of Letters'latent.

Patented Nov. 18, 1913.

Application flled l'ebruary 11,-1918. Serial No. 747,887.

7b allwhom htmay concern:

' Be -=it known that I, FREDERICK 'G. 'KEYE'S; a citizen of'the United States, and resident of Boston ccunty of SuifolkfState of Masuseful Improvements in Mercury -'Vapor Apparatus, of which the :following is 'a specification.

My invention relates to mercury vapor lamps ada ted to operate on the principle of the we l-known Cooper Hewitt lamps and more particularly to lamps of this class operating at high i temperatures or pressures.

With the apparatus hereinafter described I' have shown a structure having two electrodes of yaporizable material and having the property of automatically maintaining "the proper distribution of the electrode material between the electrodes during normiil operation withou-tthe physical transfer? of electrode material in liquid form 'fromj one electrode to the other. i

-My appa'ratus isan improvement on oer-5 tain other device's intended to serve a similar;- function.

This feature anti certain othersareshown: in the drawings of this specification or are? describedin the specification.

Figure 1 'represents a side elevation of; the lamp embodied in my invention and Fig. 2 shows-'a-planview of the same lamp. Fig. 3 shows in some detail a seal for a quartz container suitable for permitting the. entrance of electric current within the vacu-' um space. 1

In Fig. 1, I show a container having a, light giving portion, 1, an anode condensing chamber, 2, a cathode cooling chamber, 3, and seals, 9. This'container is frequently made of transparent or partially transparent silica or fused quartz, though other materials such as a relatively high melting glass may be used'without departing fro-rn my invention.

The anode is shown as of mercury at 4 and the cathode as a large bodyof mercury at 5, having a small active electrode surface at 6. The seal, 9, which I constitute of a platinum cup, 14, carrying a rod, 10, both inside and outside the container, gives a hermetically tight joint and transmits with ease any current required for this device.

The details of the seal may be varied, or any preferred form of seal may -be substi-v tuted for that shown herein, it being-only necessary that the-seal should be :andremain gas-tight and should aflord 'means for good electrical conn'ection between the external electrodes. the container 1 circuit and the inside him At the cathodeend o utilize a iunnel shaped tube, closely fitted to or integral with the adjacent and ofzthe main tubular 5 portion giving and dipping "at tion as to directionfrcm theanode, 4, 130 618 cathode, 6, generating heat in-the-elect-mdes :andthe vapor .path. As is well knownthe electrodes are both heated and mercury vaporized to maintain a relatively high pressure "throughout the exhausted space. This :produces a'high voltage drop in the current path :and 'a very high temperature in the vapor thereabout which in turn heats the adjacent tubular portion' of the-container to a temperature which ishigh iIl'COIIlPfl-liSOIl with the electrodetemperature.

A portion of the heat nerated rby the current is dissipated from' epo'sitive anode condensing chamber, 2, 'to which it is carried by the mercury vapor. A portion of the heat generated is also dissipated 'at'the cathode chamber, 3, and it is desirable'that the amounts of heat so di'ssipatetl be protportioned more or lws in 'the same ratio as'the heat generated at the two'electrode's respectively. :If this condition 'be accurately attained there would be no permanent transfer of mercury from one electrode 'to the other. Since, however, this condition can not, in practice, be permanently produoed by the mere initial proportioning of the cooling surface of the anode condensing chamber and the electrode chamber, it is usually desirable tohave somesupplemental,

automatic, or self-adjusting means :for maintaining the exact proportionality required.

Such a means is supplied by the funnelshaped piece, "12.

The functioning of this device is-as ifollows: At the instant of starting, the cathode chamber will be "entirely filled owing to the tippingof the'lanlpfif we assume this lamp to be started by 't-ipping.

The arc having started, the heatcommunicared to "the funnel slraped piece cameras evaporation of cathode material and consequent transfer of cathode material to the anode chamber. When equilibrium is finally attained, it will be found that the mercury meniscus in the funnel-shaped tube is depressed and locates near the lower end of the tube and also a small free space appears in the cathode chamber. The meniscus in general will stop at the lower end, owing to the fact that the heat is then more readily communicated to the cathode material.

In operation, mercury vapor sometimes depresses the meniscus within the funnelshaped iece to such an extent that vapor bubbles into the cathode chamber and condenses there. This action causes the a ita- 'tion of the mercury within the cat ode chamber and serves two purposes; first, the mercury being in contact with the funnelshaped piece inside the cathode chamber, serves to keep the latter comparatively cool, thus retarding the disintegration of said funnel-shaped piece; and, second, it is obvious that the agitation of the mercury in the cathode chamber incident to this bubbling of the vapor mentioned, tends to cause a more rapid equalization. of temperature throughout the mass of mercury and hence a more rapiddissipation of heat.

While I do not wish to make a definite conclusion as to the theory as to why equilibrium is attained when the mercury level within the tube becomes de ressed to the point indicated, it appears to e related to the variations produced in the heat dissipating capacity of the cathode chamber with variations in the level and freedom of entrance of mercury vapor into the-cathode chamber from the main tubular portion. The amount of heating of this tube can be controlled by varying the thickness of the tubular portion of the piece 12, which varies the capacity thereof for. conducting heat to the mercury 5. Arather heavy wall is sometimes found desirable at this point.

In F i 2 are shown in plan the same elements t at are shown in Fig. 1, similar reference characters being used. I may add that the part 11 is a trough' formed in the container to expose in the direction toward the cathode only a narrow anode surface so that the motion of the end of the current path is restricted and flickerin is reduced. It is generally desirable to thic en the material of the container just above the anode as at the oint, 7, which is a point of relatively higii temperature. I frequently provide a ring or ridge, 8, around the seal chambers to facilitate the securing of a cap for protecting the leading-in wires and mechanically supporting the external lead.

In Fig. 3 the sealv chamber is shown enlarged, 16 representing an extension of the container with the" rim or ridge 8 utilized for securing the seal cap. At 14 I use a small very thin platinum cup, or tube, closed at one end. The thickness of this may not exceed one or two thousandths of an inch in some cases. \Vhen the container is made of quartz, in order to produce a safe and tight connection between the wall of the container and the platinum tube I use an intermediate section, 13, of the seal chamber made of material ca able of making a tight joint with the wal of the part 16, and also with the thin platinum cup 14. For this material I may use a glass made of a glass mixture of quartz with a portion of some other glass capable of being joined to fused quartz. This may be formed by melting together one part magnesium borate and about twenty parts of ground fused silica. This produces -a material which can be sealed to quartz and which also will adhere to platinum when formed as here shown. When the glass is shaped into a cylinder as shown at 15 and melted about the thin platinum tube, the platinum tube will be somewhat stretched on the cooling down after the formation of the seal. In operation this stretchin is somewhat relieved by the heating up 0 the seal chamber. In this connection it should be stated that the thickness of the platinum should be so adjusted that cohesion between the metal and the glass persists when the seal is cooled down. It is often desirable to utilize in the hollow of the closed tube, 14, a conducting rod, such as shown at 10 in Fig. 1 and a similar rod, or connection may be attached to the outside of the platinum by silver solder or other means.

While I have shown and described a certain specific apparatus embodying my invention, ;I do not wish to limit its use to these special structures, but contem late that any apparatus producing the a vantageous results of this invention by equivalent means may come within its scope. For example other materials than mercu may be used for electrodes, devices may e operated at other temperatures, or for various the neighborhood of and draining into said anode, a cathode at the other end of said tubular portion, a cooling chamber at said cathode and a funnel sha ed diaphragm between said cathode chamber and said tubular portion, said funnel shaped piece having its small end dipping under the surface of said cathode.

2. In a vapor electric apparatus havin a plurality of liquid electrodes, means or maintaining the normal quantity of electrode material at an electrode, said means comprisin a funnel shaped diaphragm traversed y the normal current flow, an

10 active electrode surface within said funnel shaped diaphra and means for producin a graduate rise of temperature along said funnel sha ed diaphragm.

Signed at ew York in the county of New York and State of New York this 7th 15 day of February, A. D. 1913.

FREDERICK G. KEYES. Witnesses:

P. H. THOMAS, THOS. H. BnowN. 

